It is known in the art to provide positive crankcase ventilation (PCV) systems for internal combustion engines to reduce emission of contaminants by drawing crankcase vapors from the engine crankcase into the engine cylinders for burning. This is typically done by venting the vapors through a cylinder head cam cover attached to the crankcase to an intake air passage, such as an intake manifold, via a passage member such as a PCV tube. A typical PCV system may include a PCV control valve or orifice mounted in the flow path between the crankcase and the air intake portion. During engine operation, a vacuum is developed in the manifold which draws crankcase vapors through the PCV system into the manifold where it mixes with intake air to be delivered to the engine cylinders. In designing a PCV system, it is important to ensure that noise levels caused by flow through the system are acceptable and that component costs are minimized.